text: """
  You are playing the following Bulls and Cows game with your friend: You write down a number
  and ask your friend to guess what the number is. Each time your friend makes a guess, you
  provide a hint that indicates how many digits in said guess match your secret number exactly
  in both digit and position (called "bulls") and how many digits match the secret number but
  locate in the wrong position (called "cows"). Your friend will use successive guesses and
  hints to eventually derive the secret number. Write a function to return a hint according to
  the secret number and friend's guess, use A to indicate the bulls and B to indicate the cows. 
  
  Please note that both secret number and friend's guess may contain duplicate digits.
  
  Note: You may assume that the secret number and your friend's guess only contain digits, and
  their lengths are always equal.
  """
  from collections import Counter
  
  
  class Solution:
      def getHint(self, secret, guess):
          As = sum([x==y for x,y in zip(secret, guess)])
          sec_c = Counter(secret)
          gue_c = Counter(guess)
          As_and_Bs = sum([min(sec_c[elem], gue_c[elem]) for elem in sec_c])
          return str(As) + "A" + str(As_and_Bs-As) + "B"
  
  
  if __name__ == "__main__":
      secret = "1807"
      guess = "7810"
      out = "1A3B"
      # Explanation: 1 bull and 3 cows. The bull is 8, the cows are 0, 1 and 7.
      res = Solution().getHint(secret, guess)
      assert res == out, (res, out)
  
      secret = "1123"
      guess = "0111"
      out = "1A1B"
      # Explanation: The 1st 1 in friend's guess is a bull, the 2nd or 3rd 1 is a cow.
      res = Solution().getHint(secret, guess)
      assert res == out, (res, out)